Lawrence (16), a pupil at Otago Boys High School, will join club-mate Rebekah Greene in the 20-strong New Zealand team.
He was given the news by his coach, Brent Ward.
"I'm pleased ," Lawrence said.
"It will be an amazing experience for me."
Lawrence will compete in the 100m and the medley relay.
His best legal 100m time is 11.30sec and he has run 22.9sec for the 200m.
It will be the first time Lawrence has competed for New Zealand and the first time he has been to Australia.
The Oceania championships are being held in conjunction with the Australian junior championships at the Sydney Olympic Park.
It is the qualifying event for the International Olympic Committee's Youth Olympic Games in Singapore from August 14-26.
Lawrence is noted for his ability in relays and was a member of the Otago Boys 4x100m team that broke a record at the Otago secondary schools champs at the Caledonian Ground on Saturday.
He was also in the school team that won the gold medal in the senior boys 4x100m relay at the New Zealand secondary schools champs in Timaru in December.
Lawrence was born in Dunedin, but his mother grew up in Fiji and he possesses the speed and rugby-playing ability often associated with that country's athletes.
He played on the wing for the Otago Boys First XV last year and was also a member of the Otago under-16 team.
Greene (16), who has been in outstanding form this season, will compete in the 3000m and the 1000m.
She is sixth on the national senior women's ranking list with a best time of 9min 30.69sec.
She tops the table in her age group.
Greene showed she has the temperament for athletics at the transtasman meeting in Auckland where she set Otago records in six age categories when she ran the 1500m in 4min 21.98sec.
Greene is the Otago senior women's record holder in the event after beating the time set by Gail Metzger (Hill City) in 1986.
Greene was coached by former Australian Jim Baird but has recently switched to Maria Hassan, of Christchurch, the Athletics New Zealand event coach for middle distance.
